Spinach (Spinacia Oleracea) is an annual flowering plant which, despite its looks resembling a green leafy vegetable, does not belong to the cruciferous family like collard greens, kale, mustard greens, turnip greens, or arugula veggies.
It belongs instead to the chenopod or amaranth family along with beet greens and Swiss chard as well as the grains amaranth and quinoa.
Raw spinach is 91% water, 4% carbohydrates, 3% protein, and negligible fat.
However, it is most famous for its considerable amount of iron, attaining 21% of the Daily Value in a 100 g (3.5 oz) amount of raw spinach.
Spinach is also used as a green natural, vegetal, green food colorant.
References: Read more about Spinach on Wikipedia